It is known to make an airplane floor using horizontal crossmembers that extend perpendicularly to the longitudinal direction of the fuselage. Longitudinal rails are fastened on the crossmembers, and in turn they are covered by a floor panel. The rails support the passenger seats.
Numerous systems or members generally need to be fastened to the floor. For example, these may be hydraulic or pneumatic members (compressed air or air conditioning ducts, water ducts, refrigeration ducts, oxygen ducts), electric cables, fire extinguisher circuit elements, or indeed cables of on-board communications networks. These various members are generally located under the crossmembers of the floor. A covering panel masks and protects these members relative to a cargo zone.
The drawback of that arrangement is that it occupies a considerable amount of height, thereby penalizing the height available in the cabin space above the floor or the height available in the cargo space below the floor.